Screening for Aliens   3 comments

Felipe del Bosque Blog September 10th 2012

The Calm Before

It has been another week of sun and showers.  The thunderstorms have still been around but now not every night as has been the case over the past few weeks and they have been further off  in the distance.  Towards the end of the week and over the weekend there was no rain to speak of at all.  So far in terms of precipitation it has been and looks like being one of the drier wet seasons.  But there is still another 2 or 3 months to go before we can say as to whether it was or wasn’t.  For anyone visiting Costa Rica, particularly the Osa Peninsula, at the moment though, if their research had lead them to believe they were in for a soaking, they are going to have a very pleasant surprise.

There is a Light On

One evening when I left my cabin as the sun was setting I forgot to switch off the light.  I was away for several hours searching for animal life around the grounds and when I returned it was to find that the incandescent glow coming from within the 4 walls of my abode had attracted the collective presence of a wide variety insect life.  They had come up against the fine mesh screens covering my windows and there they had come to rest.  Anyone living in unlit areas will be familiar with this phenomenon.

One unusual visitor was a butterfly that must have been flying close by and having seen the light was attracted to its source before settling and becoming dormant.  This was one of the owl butterflies, (Opsiphanes tamarindi).  This is a fairly common species often found in the areas of their larval food plant Heliconias, several species of which my garden grow abundantly in my garden.  They are also crepuscular, more often than not flying at dusk, which this one appears to have been doing before landing on my window screen.  It is noticeable that the trailing edge of the hind wing is missing where a predator must have taken a bite in the area of the eye spot, a deliberate target presented by the butterfly to the predator to direct the bite away from the vitally important head and body.

Owl Butterfly

Looking at the photograph of the full side view, the butterfly would only appear to have 2 legs each side whereas everyone knows that insects have 6 legs, 3 each side.  If you then look at the close up of the head, which the butterfly was so amenable to pose for, you will see that there is indeed a third leg.  The front legs are reduced in size and are held up in front of the eye either side of the proboscis.  They are covered in hairs and give the large and cosmopolitan family of butterflies that this species belongs to its name, the brush foot butterflies, (Nymphalidae).

Opsiphanes tamarindi

A large number of katydids of varying size and species were aggregated on the screen near the owl butterfly.  One weird looking insect, a planthopper was also making its way up the screen.  Both this and the katydids exhibit cryptic coloration that blends them perfectly against the background vegetation amongst which they live.  The katydid’s body is green and leaf shaped whereas the planthopper has its wings bearing a heavy network of dark green contrasting against the lighter green background resembling a mesh of leaf veins.  The border is red with some red spots towards the inside which may serve to suggest some fungal damage or decay.  I stand to be corrected by I think this particular planthopper belongs to the family Flatidae and may be of the genus Lawana.

Unidentified Katydid

Unidentified Planthopper

Tremulous Lawn Gel

One morning while out conducting my daily survey of plants and animals, I noticed in the grass a blob of gelatinous material like a piece of shredded jelly.  The organism was in fact a jelly fungus, Tremella fuciformis.  There is nothing else that actually resembles Tremella so it is easy to identify.  It is generally associated with rotten wood in high humidity but this particular one seemed to growing straight out of the ground. In fact Tremella has the strange habit of parasitizing other fungi that are living saprophitically on decaying roots and branches.

Tremella fuciformis

It is not considered a delicacy many places outside of China where it is grown commercially and consumed in large quantities.  It is also used medicinally in China, more recently for counteracting the harmful effects of radiotherapy.

Not My Stepping Stone

For many months now I have been trying to get a photograph of a large male Basilisk, (Basiliscus basiliscus), that resides at the Bosque pond.  I always see him sleeping at night on a high vertical root of the large Screw Pine growing at the back of the pond but I really wanted to capture him awake at the pond edge.  Every time I got close enough he would take fright and disappear from view at high speed.  On this day though, I could see him sitting in the sun in his usual place at the rear of the pond.  I raised the camera to my eye and hit the release button.  Then I took a few steps closer and shot another picture.  He knew I was there but at this point remained compliant with my desire to capture his image in profile.  I took a few more steps and then took another picture.  I was now at the front edge of the pond and he at the far side, a distance of about 6 feet.  He started to get nervous, lifted his head, I took one more picture and then he was gone.  But at least now I have one decent photograph of him.

Basilisks are iganian lizards that prefer a watery habitat and can commonly be found around bodies of water, creeks and rivers.  They grow to approximately 3 feet in length and are generally found foraging for food around aquatic habitats.  They are omnivores hunting everything from arthropods, fish, amphibians, small reptiles, birds and a wide variety of vegetative material.

Basiliscus basiliscus

The adult males have the distinctive crest at the back of the head as well as the impressive fan that runs down the back and the dorsal surface of the tail.  These features are missing in both the juveniles and females of all ages.  They are known by many as Jesus Christ lizards due to their ability to run across the surface of the water without breaking the surface tension.  The young ones are much more adept at this than are their adult peers who given a good run at it may make some distance before succumbing to the effects of gravity, fall forwards and finally have to swim the rest of the way.

Final Fruit

The bumper crop of mangos, rambutans and star fruit from trees around the grounds that have graced the dishes in the restaurant over the past 3 or 4 months has now dwindled to a few remaining hanging from the trees, their taste long lost with the dying sunny days.  Some fallen mangoes still lie fermenting on the ground under the trees that bore them.  Their fermenting remains are providing one last feast for several creatures.  At night an occasional Crab-eating Raccoon, (Procyon crancrivorus), can be seen eating the fallen fruit, occasionally in the company of the Common Opossum, (Delphis marsupialis).  Kinkajous, (Poto flavus), and some of the monkeys particularly White-faced and Spiders are taking the last remaining fruit in the trees.  One night I saw a female Crab-eating Raccoon bring her 2 new offspring to share in the pungent feast.

Mango with bees

The next day on the ground I could see a fallen mango that had a huge number of bees feeding from the pulp.  The bees were uniformly black and were probably Stingless Bees of the tribe Meliponini belonging to the family Apidae, (which also contains the honey bees).  Again with due care and respect, I managed to get very close for the photograph.

Finally when returning back to my cabin there was a tiny spider on the ground which when it saw me, turned to face me and then gave that look that only a jumping spider can.  The anterior pair of eyes is very large and provides the binocular vision vital to an arachnid that stalks and then leaps upon its prey like miniature eight-legged tiger.


The hind legs are short and powerful enough to allow the spider to jump some distance relative to its body size.  The front legs are long and designed to catch the prey generally before it knows what has happened.  The jumping spiders always attach a piece of silk before they leap into another creatures oblivion so secure them incase they should become dislodged.

Philip is a biologist, writer and photographer as well as the onsite naturalist guide at Bosque del Cabo Rainforest lodge on the Osa Peninsula, Costa Rica.

Photo Feature

Almost Stung Again

Last week I posted on the blog some pictures and a short article about Long-waisted Wasps.  If you are careful and look diligently under the leaves of low growing plants you will find that there are a great many paper wasp nests in the area.  I noticed another nest not too far from the restaurant but with some of the Polistes paper wasps attending this one.  The nest was in an awkward place to photograph but with a bit of cautious maneuvering I knew I could access it and hopefully without antagonizing the vengeful little bearers of a venom laden stinger.  I managed to get quite close and obtain some pictures before accidently knocking the leaf under which they were perched.  At one and the same time the aggressive females took to the air, their intentions solely to encourage me to depart, so I made a slow and deliberate retreat and left them to go about their business without further provocation.

Polistes sp         Paper Wasps         Polistes sp

Polistes sp         Paper Wasps         Polistes sp

Just as with Long-waisted Wasps, (which belong to the same family, Vespidae and subfamily, Polistinae), they produce unenclosed nests of chewed up plant fiber composed of one comb with a varying numbers of cells.  There will be one queen whose dominance is asserted over the other females in attendance by fighting.  Initially there may be several females capable of reproduction and as fast as they lay eggs their rivals consume them.  The fastest eater wins and becomes queen.

Paper Wasp

Text and Photographs are taken from the forthcoming book:

The Natural History of Bosque del Cabo by Philip Davison

Temperature and Rainfall

Average Daily Rainfall 0,21 ins.  Total Weekly Rainfall 1.48 ins

Average Daily Rainfall 5.38 mm.  Total Weekly Rainfall 57.68 mm

Highest Daily Temp 89°F.  Lowest Daily Temp 74°F.

Highest Daily Temp 31.7°C.  Lowest Daily Temp 23.0°C.

Species List for the Week


  • Howler Monkey
  • Spider Monkey
  • White-faced Monkey
  • Crab-eating Raccoon
  • Kinkajou


  • Mealy Amazon
  • Red-lored Amazon
  • Scarlet Macaws
  • Great Curassow
  • Pale-billed Woodpecker
  • Black-hooded Antshrike
  • Short-billed Pigeon
  • White-tipped Dove
  • Long-billed Hermit
  • Purple-crowned Fairy
  • Stripe-throated Hermit
  • Red-capped Manakin
  • Chestnut-mandibled Toucan
  • Dusky-capped Flycatcher
  • House Wren
  • Riverside Wren
  • Great Tinamou
  • Black Vulture
  • Turkey Vulture


  • Boa constrictor
  • Cat-eyed Snake
  • Central American Smooth Gecko
  • Central American Whiptail
  • Clawless Gecko
  • Common Basilisk
  • Four-lined Ameiva
  • Golfo Dulce Anolis
  • Terciopelo


  • Banana Frog
  • Black and Green Poison Arrow Frog
  • Fitzinger’s Rain Frog
  • Gladiator Frog
  • Golfo Dulce Poison Arrow Frog
  • Marine Toad
  • Red-eyed Green Tree Frog
  • Smoky Jungle Frog


  • Anartia Fatima
  • Anartia jatrophae
  • Arawacus lincoides
  • Archaeoprepona demophon
  • Cissia confusa
  • Consul fabius
  • Glutophrissa Drusilla
  • Heliconius cydno
  • Heliconius erato
  • Heliconius ismenius
  • Heliconius sapho
  • Hermeuptychia hermes
  • Junonia evarete
  • Morpho helenor
  • Morpho Menelaus
  • Parides erithalion
  • Perophthalma lassus
  • Philaethria dido
  • Phoebis argante
  • Phoebis sennae
  • Pyrgus oileus
  • Pyrrhogyra crameri
  • Siproeta stelenes
  • Taygetis Andromeda
  • Urbanus simplicius
  • Urbanus tanna


  • Alamandra  cathartica Flowering
  • Alpinia purpurata Flowering
  • Apeiba tibourbou Flowering
  • Arachis pintoi Flowering
  • Arundina graminifolia Flowering
  • Bauhinia variegata Flowering
  • Cananga odorata Flowering and Fruiting
  • Cascabella thevetia Flowering
  • Citrus spp  Fruiting
  • Clusia rosea Fruiting
  • Clusia vallerii Fruiting
  • Cocos nucifera Flowering andFruiting
  • Crestentia alata flowering and Fruiting
  • Costus specioas Flowering
  • Couroupita guianensis Flowering and Fruiting
  • Dypsis lutescens Flowering and Fruiting
  • Etlingera elatior Flowering
  • Ficus insipida Fruiting
  • Heisteria accuminata Fruiting
  • Heliconia chartacea Flowering
  • Heliconia latispatha Flowering
  • Heliconia pogonantha Flowering
  • Heliconia psittacorum Flowering
  • Heliconia rostrata Flowering
  • Hibiscus rosa-sinensis Flowering
  • Hymenaea coubaril Fruiting
  • Hymenocallis littoralis Flowering
  • Ixora coccinea Flowering
  • Lacmellea panamensis  Fruiting
  • Lantana camara Flowering andFlowering
  • Lagerstroemia speciosa Fruiting
  • Mangifera indica Fruiting
  • Musa acuminate Flowering andFruiting
  • Naucleopsis ulei Fruiting
  • Nephelium lappaceum Fruiting
  • Piper auritum Flowering and Fruiting
  • Piper nigrum Fruiting
  • Piper umbellatum Flowering and Fruiting
  • Pleiostachya pruinosa Flowering
  • Plumeria rubra Flowering
  • Psidium guajava Fruiting
  • Psychotria sp Fruiting
  • Stachytarpheta frantzii Flowering
  • Terminalia catappa Flowering
  • Thunbergia grandiflora Flowering
  • Zammia sp Flowering

3 responses to “Screening for Aliens

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  1. Hi Philip!

    Is your cabin really lit by incandescent light (and not compact fluorescent like the rest of the lodge)? Do you notice a difference in the variety of wildlife attracted to the different spectrums produced by various lighting sources (incan, fluorescent, LED, candles, etc.)?


    Michael Clervi


    • Hi Michael
      I use a 60 watt incandescent bulb in my reading lamp. I prefer the color to read by at night. I have not done any work to assess the attractive qualities of different light sources but moth traps use U.V. with a white sheet to attract insects.
      Hope married life is going well.
      Best wishes, Philip


  2. Fascinating stuff! I love the jelly fungus and bees feeding on the mango.


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